The method of the invention consists of a sequence of operations for renewing the surface layer of a conventional road surface, conventional in the sense of a layered surface of thickness varying between 3 cm and 8 cm, deposited either on an underlying support layer of thickness varying between 15 cm and 30 cm or directly on a foundation in the form of non-bituminous mix or stabilized granular mix.
The method is based on immediately and directly recycling the material removed by scarification, after cold-mixing it with an aqueous bitumen emulsion, it thereby differing from known methods which require hot-mixing of the solid material with molten bitumen.
The conventional methods for renewing damaged road surfaces comprise the following operations using the stated equipment:
(a) preparing the bituminous mix by hot-mixing bitumen, sand and various inerts together in a suitable fixed plant and loading the mix into containers suitable for transportation;
(b) transferring the bituminous mix from the fixed plant of operation (a) to the laying site by trucks;
(c) loading the material brought on site into a vibrofinishing machine which applies the mix to the road bed after spraying it with bituminous emulsion to facilitate adhesion of the mix to the road bed;
(d) spreading the bituminous mix by a levelling screw and then rolling it to the thickness of the layer to be deposited.
In the conventional methods of the aforesaid type, not more than 50% of the material removed from the road surface can be reused.
In a known improved method described in Italian patent application No. 3520 A/82 in the name of the inventor of the present application, the method is implemented using a single self-propelled operating unit which removes the surface layer to be replaced, and mixes the removed material with molten bitumen at a temperature on the order of 140.degree. C. to obtain a bituminous mix which is applied directly for forming the new road surface.
This system has the great advantage of dispensing with the need for transporting the scarified material (rubble) of the removed road surface to the fixed plant for its mixing with fresh bitumen and the subsequent transporting of the bituminous mix to the site on which it is to be used.